Lubricant



Patented June 17,1947

LUBRICANT Thomas H. Rogers, Roger W. Watson, and James W. Starrett,(3111 8 11L, assignora tostandard Oil Indiana Company, Chicago, IlL, acorporation of No Drawing. Application May a, 1944, Serial No. 534,090

This invention relates to improvements-in lubricants, particularly tolubricants containing hydrocarbon oils such as mineral oils which arenon-corrosive and resistant to oxidation. More particularly the presentinventionis directed to lubricants which are resistant to the formationof gums, resinous and varnish-like materials and which are non-corrosiveto alloy bearings of the copper-lead type. 1

Many oils are not well suited as lubricants for use in internalcombustion engines, particularly those of the type operating undersevere operating conditions since under such severe operating conditionsthe oils are susceptible to deterioration resulting in the developmentof carbonaceous and/or resinous or similar varnish-like deposits in theengine and on and about the valves and rings of the engine. Furthermore,such lubricants are often corrosive, particularly to alloy bearings ofthe type such as copper-lead, cadmium-silver, etc., which are frequentlyused in such engines.

It has heretofore been discovered that certain reaction products of aphosphorus sulfide and a hydrocarbon, particularly an olefin or anolefin polymer when added to a mineral oil in small amounts incombination with small amounts of elemental sulfur or an organic sulfurcompound, are effective in inhibiting the formation of varnish; sludge,carbon and the like in lubricating oils during use and in general areeflective in inhibiting corrosion to metal surfaces in contact with suchoils. The use of the combination of the reaction products of aphosphorus sulfide and a hydrocarbon and an organic sulfur compound orelemental sulfur in lubricants is the subject matter of U. S. Patent2,316,090 granted to Charles D. Kelso and Lawson W. Mixon April 6, 1943.However, it has since been found that under certain conditions,particularly in engines operating on leaded motor fuels, lubricantscontaining the reaction products of a phosphorus sulfid and ahydrocarbon, particularly the neu tralized reaction products, andcertain organic combustion engines which do not form car- 19 Claims.(01. 252-32.?)

bonaceous deposits or resinous, varnish-like materials on and aboutv thevalves, pistons and rings of such engines and which are not corrosive tometals, particularly alloy bearing metals of the copper lead type. 7Still another object of the invention is to provide a combination ofadditives for lubricants which will materially inhibit the formation ofcarbonaceous deposits and/or res- A inous, varnish-like materials andwhich will renized turpentine, sulfurized pinene, sulfurized turpinol,sulfurized camphene and the lik or mixtures of terpenes. We prefer touse as starting material terpenes comprising a major part of dipentenes.

The sulfurlzed terpenes can be'prepared by sulfur-icing the desiredterpene by any one of various sulfurizaticn processes. Among thesulfurization processes which can suitably be employed is that oftreating the terpene with sulfur and hydrogen sulfide in the presence ofwater or steam at temperatures within the range of about 250 F. to 450F. and at pressures up to about 1500 pounds per square inch for aperiodof 1 to 10 hours. The sulfurized terpene can also be prepared bytreating the desired terpene with a sulfur chloride, such as S201: orS012, at a temperature within the range of about F. to about 250 F. Whenthe terpene is sulfurized with a sulfur chloride, the chlorine presentin the sulfurized material can be removed by treating the sulfurizedmaterial in .a bomb .at a temperature of about 300 F. to about 400 F.with ammonia or other aqueous or alcoholic alkalies, alkali metalsulfides and polysulfides, such as a sodium sulfide, or other bases. Thesulfurized terpenes which are best suited for the herein-describedpurpose are those which have a sulfur content of from about 5% to about45% or more and which show slight sulfur activity, as defined below, at210 F. with increasing activity at higher temperatures, and show adecided activity at temperatures of the order of about 300 F. or higher.

We have found that the sulfurized terpenes may be characterized by theiractivity toward copper at various temperatures. empirically evaluatedbyimmersing a polished copper strip in a mineral oil containing thesulfurized terpene and examining the strip periodically. The moredesirable sulfurized terpenes show little activity toward copper at 210F.

' when used in relatively low concentrations, e. g.

up to 2% in oil, but quickly darken a; copper strip at 300 F. when usedin the same concentrations. The sulfurized terpenes containing activesulfur, as measured by rapid darkening of the copper strip at 300 F. areefi'ective corrosion inhibitors in the engine when used inconcentrations as low as 0.5%. sulfurized terpenes containing lessactive sulfur are also efiective corrosion inhibitors in the engine butordinarily higher concentrations are required. The sulfur activity ofthe sulfurized terpenes may 'be increased by heating thesulfurizedmaterial to temperatures of from about 300- F. to about 450 F. Sulfuractivity of the sulfurized terpenes can also be increased by distillingthe sulfurized terpene under conditions whereby the high sulfur-bearingfractions are concentrated in a 40% to about 95% bottoms. The sulfurizedterpenes can also be concentrated by blowing the same with agas attemperatures of about 150 F. to about 350 F. We have found thatsulfurized terpenes having a sulfur content above about 25% andpreferably about 30% to about 40% or higher are most suitable when it isdesired to employ low concentrations of the sulfurized terpenes in thefinished lubricant.

The neutralized phosphorus sulfide-hydrocarbon reaction product canbeemployed in amounts I 'within the range of from about 0.001% to about10% and preferably from about 0.01% to about 3% and the sulfurizedterpene can be employed in combination with the neutralized phosphorussulfide-hydrocarbon reaction product in amounts of from about 0.01 toabout 5% and preferably from about 0.1 to about 2%. In addition to theneutralized reaction product of the phosphorus sulfide and ahydrocarbon, the composition-may contain in addition to the sulfurizedterpenes small amounts, for example from about 0.001% to about 5% ofelemental sulfur or other organic sulfur compounds such as a sulfurizedmineral oil or a sulfurized olefin polymer. The amount of additives inthe lubricant composition as expressed herein and in the appended claimsis based on a weight percentage.

As was aforesaid, one 'of the components of the improved lubricant isthe neutralized reaction product of a hydrocarbon with a phosphorussulfide such as P283, P483, P4 S7, or other phosphorus sulfides andpreferably phosphorus pentasulfide, Past. The hydrocarbon constituent ofthis reaction is preferably a mono-olefin hydrocarbon polymer resultingfrom the polymerization of low molecular weight mono-olefinichydrocarbons or isomono-olefinic hydrocarbons such as propylenes,butylenes, and amylenes or the copolymers obtained by the polymerizationof hydrocarbon mixtures containing isomono-olefins and mono-olefins ofless than 6; carbon atoms. Ihe polymers may be obtained by thepolymerization of these oleflns or mixtures of olefins in the presenceof a catalyst such as sulfuric acid, phosphoric acid, boron fluoride,aluminum'chloride or other similar halide catalysts of theFriedel-Crafts type.

The polymers employed are preferably monoolefin polymers or mixtures ofmono-olefin polymers and isomono-olefin polymers having me- This may belecular weights ranging from about 150 to about 50,000 or more, andpreferably from about 500 to about 10,000. Such polymers-can beobtained.

for example, by the polymerization in the liquid phase of a hydrocarbonmixture containing mono-olefins and isomono-olefins such as butylene andisobutylene at a temperature of from about F. to about F. in thepresence of a metal halide catalyst of the Friedel-Craftstype such as,for example, boron fluoride, aluminum chloride and the like. In thepreparation of these polymers we may employ, for example, a hydrocarbonmixture containing isobutylene,

butylenes and butanes recovered from petroleum gases especially thosegases produced in the cracking of petroleum oils in the manufacture ofgasoline.

A suitable polymer for the reaction with phosphorus sulfide is theproduct obtained by poly- .merizing in the liquid phasea hydrocarbonmixture containing butylenes and isobutylenes' together with butanes andsome C3 and C5 hydrocarbons at a temperature between about 0 F. and 30F. in the presence of aluminum chloride. A suitable method for carryingout the polymerization is to introduce the aluminum chloride into thereactor and introduce the hydrocarbon mixture cooled to a temperature ofabout 0 F.

into the bottom of the reactor and passing it upwardly through thecatalyst layer while regu lating the temperature within. the reactor sothat the polymer product leaving the top of the reactor is at atemperature of about 30 F. After separating the polymer from thecatalyst sludge and unreacted hydrocarbons, the polymer is fractionatedto obtain a fraction of the desired viscosity such as, for example, fromabout 80 seconds to about 2000 seconds Saybolt Universal at 210 F.

Another suitable polymer is that obtained by polymerizing in the liquidphase a hydrocarbon mixture comprising substantially C3 hydrocarbons inthe presence of an aluminum chloride complex catalyst. The catalyst ispreferably prepared by heating aluminum chloride with isooctane. Thetemperature in the reactor is controlled within the range of about 50 F.to about F. The hydrocarbon mixture is introduced into the bottom of thereactor and passed upwardly through the catalyst layer. The propane andother saturated gases pass through the catalyst, while the propylene ispolymerized under these conditions. The propylene polymer can befractionated to any desired molecular weight, preferably from about 500to about 1000 or higher.

Other suitable polymers can beobtained by polymerizing a hydrocarbonmixture containing about 10% to'about 25% isobutylene at a temperatureof from about 0 F. to about 100 F.

and preferably 0 F. to about 32 F. in the Dresence of boron fluoride.After the polymerization tionated under reduced pressure into fractionsof increasing molecular weights, and suitablei fractions obtainedreacted with the phosphorus sulfide to obtain the desired reactionproducts. The bottoms resulting from the fractionation of the polymerwhich may have Saybolt Universal viscosities at 210 F. ranging fromabout 50 seconds to about 10,000 seconds, are well suited for thepurpose of the present invention.

Essentially paraffinic hydrocarbons such as bright stock residuums,lubricating oil distillates, petrolatums, or paraflin waxes may be used.There can also be employed th condensation products of any of theforegoing hydrocarbons, usually through first halogenating thehydrocarbons, with aromatic hydrocarbons in the presence of anhydrousinorganic halides, such as aluminum chloride, zinc chloride, boronfluoride and the like.

Examples of high molecular weight oleflnic hydrocarbons which can beemployed as reactants are cetene (C16) cerotene (C26) melene (C30) andmixed high molecular weight alkenes obtained by cracking petroleum oils.

Other preferred olefins suitable for the preparation of theherein-described phosphorus sulfide reaction products are olefins havingat least 20 carbon atoms in the molecul of which from about 13 carbonatoms to about 18 carbon atoms, and preferably at least carbon atoms,are in a long chain. Such olefins can be obtained by the dehydrogenationof parafiins, such as by the cracking of paraffin waxes, or by thedehalogenation of alkyl halides, preferably long chain alkyl halides,particularly halogenated paraflin Waxes.

The olefins obtained by dehalogenation of long chain alkyl halides arepreferably those obtained by dehalogenation of monohalogenated waxes,such as, for example, those obtained by dechlorination of monochlorparaffin wax. The alkyl halides are decomposed to yield olefinsaccording to the reaction in which n is a. whole number, preferably 20or more, and X is'an halogen. It is preferred to employ parafiin waxeshaving at least about 20 carbon atoms per molecule, and melting pointsupwards from about 90 F. to about 140 F.

To obtain the halogenated parafiin wax, for example, chlorinatedparaffin wax, chlorin is introduced into the wax, maintained in a moltenstate, until the wax has a-chlorine content of from about 8% to about15%. The chlorinated wax product is a mixture of unchlorinated wax,monochlor wax and polychlor wax. This chlorinated product may be used assuch, but it is advantageous to use the substantially monochlor waxfraction. The monochlor wax fraction can be segregated from theunchlorinated wax and the polychlor wax fractions by taking advantage ofthe difierences in the melting points of the various fractions, sincethe melting point of the wax varies with the extent of chlorination, 1.e. the melting point of the unchlorinated wax is greater than that ofthe monochlor wax, and the melting point of the latter is greater thanthat of the polychlor wax. Thus, the monochlor paraffin wax can beseparated from. the unchlorinated and the polychlor wax fractions bymeans such as sweating, fractional distillation, solvent extraction,solvent precipitation, and fractional crystallization.

-- the latter as hydrogen chloride.

corresponding olefin is obtained from the monochlor parafiin wax byremoving the chlorine from The monochlor wax can be dechlorinated byheating to a temperature of from about 200 F. to about 600 F. in thepresence of a dechlorinating agent such as an alkali metal'hydroxide oran alkaline earth metal hydroxide or oxide. Other alkaline inorganic ororganic materials can also be used. The chlorine can also be removedfrom the chlorowax by heating the same for a prolonged period in theabsence of any dechlorinating agent. After the dehalogenation has beencompleted the olefin so obtained can be further purified by removing thedehalogenating agent by means of filtration or by other suitable means.

As a starting material there can be used the polymer or syntheticlubricating oil obtained by polymerizing unsaturated hydrocarbonsresulting from the vapor phase cracking of parafiin waxes in thepresence of aluminum chloride which is .fully described in United StatesPatents Nos.

1,995,260, 1,970,002, and 2,091,398. Still another type of olefinpolymer which may be employed is the polymer resulting from thetreatment of vapor phase cracked gasoline and/or gasoline fractions withsulfuric acid or solid absorbents such as fullers earth wherebyunsaturated polymerized hydrocarbons are removed. Also contemplatedwithin the scope of this invention is the treatment with phosphorusulfide of the polymers resulting from the voltolization of hydrocarbonsas described, for example, in United States Patents Nos. 2,197,768 and2,191,787.

Also contemplated within the scope of the present invention are thereaction products of a phosphorus sulfide with an aromatic hydrocarbonsuch as, for example, benzene, naphthalene, toluene, xylene, diphenyland the like, or with an alkylated aromatic hydrocarbon such as, forexample, benzene having an alkyl substituent having at least four carbonatoms and preferably at least eight carbon atoms such as a long chainparafin wax. -The phosphorus sulfide-hydrocarbon reaction product can bereadily obtained by reacting a phosphorus sulfide, for example P255 withthe hydrocarbon at a temperature of from about 200 F. to about 500 F.and preferably from about 200 F. to about 400 F., using from about 1% toabout 50% and preferably from about 5% to about 25% of the phosphorussulfide in the reaction. It is advantageous to maintain a non-oxidizingatmosphere such as, for example, an atmosphere of the product byfiltration or by dilution with asolvent such as hexane, filtering andsubsequently The high molecular weight olefins are obtained by removingthe halogen as hydrogenhalide from the halogenated paramn wax. Forexample, the

removing the solvent by suitable means such as by distillation. Ifdesired the reaction product can be further treated with an agent havingan active hydrogen atom such as steam at an elee vated temperature offrom about F. to about 600 F.

The phosphorus sulfide-hydrocarbon reaction product normally shows atitratable acidity which is neutralized by treatment with a basicreagent. The phosphorus-sulfide -hydrocarbon reaction product whenneutralized with a basic reagent containing a metal constituent ischaracterized by the presence or retention of the metal constituent ofthe basic reagent. Other metal constitua metal constituent resultingfrom said neutralization or resulting from the reaction of a heavy metalsalt with the phosphorus sulfide-hydrocarbon reaction product treatedwith a basic reagent.

The neutralized phosphorus sulfide-hydrocarbon reaction product can beobtained by treating the reaction product with a suitable basic compoundsuch a a hydroxide, carbonate or an oxide of an alkaline earth metal oran alkali metal such as, for example, potassium hydroxide or sodiumhydroxide. Other basic reagents can be used such as, for example,ammonia or an alkyl or aryl substitute of ammonia such as amines. Theneutralization of the phosphorus sulfide-hydrocarbon reaction product iscarried out preferably in a non-oxidizing atmosphere by contacting thereaction product either as such or dissolvedin a suitable solvent suchas naphtha with a solution of the basic reagent, for example, potassiumhydroxide or sodium hydroxide dissolved in alcohol. As an alternativemethod, the reaction product can be treated with solid alkalinecompounds such as KOH, NaOH, NazCOz, K2003, CaO, and the like at anelevated temperature of from about 100 F. to about 600 F. As wasaforesaid, when the phosphorus sulfide-hydrocarbon reaction product isneutralized with a basic reagent containing a metal constituent, theneutralized reaction product is characterized by the presence of themetal constituent of the basic reagent. Neutralized reaction productscontaining a heavy metal constituent such as, for example, tin,titanium, aluminum, chromium, cobalt, zinc, iron, and the like, can beobtained by reacting a salt of 'the desired heavy metal with thephosphorus sulfide-hydrocarbon reaction product which has been treatedwith a basic reagent. It will be understood that when the neutralizationis accom- As noted above it has been disclosed hereto covered thatsuperior and much more effective corrosion inhibition is obtained when asulfurized terpene, instead of the sulfur-containing organic compoundsheretofore described, is used in combination with the phosphorussulfide-hydrocarbon reaction product and particularly the neutralizedphosphorus sulfide-hydrocarbon reaction product. v

The, improvement obtained when a small amountofwsulfurized-terpene isused in combination with a neutralized phosphorus sulfidehydrocarbonreaction product is illustrated by the data presented in the followingtable. The data presented therein are those obtained in the socalled 36Hour Chevrolet Test made in accordance with the Cooperative ResearchCouncil test procedure C. R. C. Designation L-4-243" of February, 1943.This test is made in a six cylinder spark-ignition internal combustionengine equipped with two copper-lead alloy bearings and operating atabout 3150 R. P. M. with anoil temperature of 280 F. 2 F. Thecopper-lead alloy bearings are weighed before the test and at the end ofthe test period and the amount of corrosion expressed in grams per fullbearing loss during the operating period. The following oils were testedby this method:

A. 'A solvent refined M. Ca 's. A E. 30 motor oil.

B. A solvent refined M. C. S. A. E. 30 motor oil containing a sumcientamount of a neutralized phosphorus pentasulfide-isobutylene polymerreaction product to give 0.042% phosphorus in th final blend.

C. B+.25% sulfurized mineral oil.

D. C+1.5% of a sulfurized isobutylene tetramer equivalent to0.09% sulfurin the final blend.

E. C+0.5% dixylyl disulflde equivalent to 0.12% sulfur in the finalblend.

F. C+0.25% ethyl xanthate disulfide equivalent to 0.13% sulfur in thefinal blend.

G. C+0.25% sulfurized terpene equivalent to 0.07% sulfur in the finalblend.

H. C+0.5% sulfurized terpene equivalent to 0.15% sulfur in the finalblend.

I. B+0.5% sulfurized terpene equivalent to 0.15% sulfur in the finalblend.

Table I Copper-Lead Alloy Bearing Duration Corrosion of Test The abovedata demonstrate the .marked corrosion inhibition effect of sulfurizedterpenes (oil samples G and I) compared with other sulfurcontainingorganic compounds. Numerous tests have shown that the presence ofsmall'amounts of sulfurized mineral oil in oil compositions such asexemplified by Examples D to I inclusive has a substantially noeffect onthe other sulfur materials in the composition; this is demonstrated bythe data obtained on .oil sample'I.

The corrosion inhibiting efi'ect of sulfurized terpenes and thesuperiority of such compounds over other sulfur-containing organiccompounds is further demonstrated by the data in Table II.

I The data in Table II were obtained in the so-- called 500 hour test"made in accordance with the Cooperative Research Council test procedure"C. R. C. Designation 1,-5-243 of February, 1943. This testis made in acompression-ignition internal combustion engine equipped with copperleadalloy bearings and operating at an engine speed of 2000 R. P. M. with anoil temperature of 230F.i2F. In this test the copper-lead alloy in thefinal blend+.2% sulfurized sperm oil equivv alent to .20% sulfur.

Table-r1 Oil Sample Bearing Corrosion Results A Copper-lead alloybearings averaged under 0.1 gram loss per full hearing at the end of the500 hour test. B Bearings so badly corroded at the end of 48 hours thetest had to be stopped to prevent serious mechanical damage to suchengine parts as shaft and connecting rods. New bearings inserted andtest continued. In 210 hours additional running period the hearings wereagain so badly corroded the test was stopped.

The results obtained in the above tests again clearly show thesuperiority of sulfurized terpenes over other sulfur-containing organiccompounds.

Although the present invention has been described as applied tohydrocarbon lubricating oils, the invention is not limited thereto butcontemplates the use of sulfurized terpenes in combination with thereaction products of a phosphorus sulfide and a hydrocarbon,particularly the neutralized reaction products thereof, in productsother than hydrocarbon lubricating oils such as, for example, fuel oil,insulating oils, turbine oils, non-drying vegetable and animal oils,synthetic oils, greases and the like. I

While the invention has been described by reference to variousrepresentative constituents and has been illustrated by reference tospecific examples thereof, the invention is not to be limited to thevarious representative compounds named or to the specific examples givenbut includes within its scope such modifications as come within thespirit of the appended claims.

We claim:

1. An oleaginous composition comprising a major proportion of ahydrocarbon oil and in combination therewith from about 0.01% to about5% by weight of a sulfurized terpene and from about 0.001% to about byweight of the neutralized reaction product of a phosphorus sulfide and ahydrocarbon.

2. A lubricant composition comprising a major proportion of ahydrocarbon oil and in combination therewith from about 0.01% to about5% by weight of a sulfurized terpene and from about 0.001% to about 10%by weight of the neutralized reaction product of a phosphorus sulfideand a hydrocarbon.

3. A lubricant composition comprising a major proportion of ahydrocarbon oil and in combination therewith from about 0.01% to about5% by weight of a sulfurized terpene and from about 0.001% to about 10%by weight of the neutralized reactionproduct of a phosphorus sulfide andan olefin.

e. A lubricant composition as described in claim 3 in which the olefinis anolefin containing at least carbon atoms in the molecule of 10 whichfrom about 12 carbon atoms to, about 18 carbon atoms are in a. longchain.

5. A lubricant composition comprising a major proportion of a.hydrocarbon oil and in combination therewith from about 0.01% to about5% by weight of a. sulfurized terpene and from about 0.001% to about 10%by weight of the neutralized reaction product of a. phosphorus sulfideand an olefin polymer.

6. A lubricant composition as described in claim 5 in which the olefinpolymer is an isobutylv ene polymer.

7. A lubricant composition as described in claim 5 in which the olefinpolymer is a propylene polymer.

8. A lubricant composition comprising a major proportion of ahydrocarbon-oil and in combination therewith from about 0.01% to about5% by weight of a sulfurized terpene, and from about 0.001% to about 10%by. weight of the neutralized. reaction product of a phosphorussulfideand an olefin polymer, said neutralized reaction product containing ametal constituent.

9. A lubricant composition as described in claim 8 in which the metalconstituent is an alkali metal.

10. A lubricant composition as described inclaim 8 in which themetalconstituent of the neutralized reaction product is potassium. 1

11. A lubricant composition as described in claim 8 in which the metalconstituent of the neutralized reaction product is sodium.

12. A lubricant composition as described in claim 8 in which the metalconstituent of the neu- 13. A lubricant composition as described inclaim a in which the metal constituent of the neuterpene and from about0.001% to about 10% by weight of the neutralized reaction product of aphosphorus pentasulfide and an olefin polymer.

.16. A lubricant composition comprising a major proportion of ahydrocarbon oil and in combination therewith from about 0.001% to about10% by weight of a metal-containing neutralized reaction product of aphosphorus sulfide and a hydrocarbon and from about 0.01% to about 5% byweight of a sulfurized terpene exhibiting high sulfur activity attemperatures of about 300 F. and higher.

17. A lubricant composition comprising a' major proportion of ahydrocarbon oil and in combination therewith from about 0.001% to aboutI 10% by weight of a metal-containing neutralized reaction product of aphosphorus sulfide and a hydrocarbon and from about 0.01% to about 5% byweight of a sulfurized terpene subjected to heat treatment to impartthereto high sulfur activity at temperatures of about 300 F. and

REFERENCES crmn The following references are of record in the file ofthis patent:

' Number UNITED STATES PATENTS Name Date Kelso Apr. 6, 1943 Zimmer Jan.5, 1943 Zimmer June 17, 1941 Kaufman June 9, 1936 Kaufman June 9, 1936Palmer Sept. 12, 1933 Kobbe Feb. 9, 1932

